It is well known that various clearer devices are provided for draft rolls in spinning machines. Those clearer devices can be classified into the top clearer device which is disposed above a draft roll section and the bottom clearer device which is disposed below the draft roll section. The former is generally placed against a set of top rolls and the latter against a set of bottom rolls. It is conventional to provide the top and bottom clearer devices of a same or different configuration, whereas only one of the clearer devices is provided as occasion may require.
Those clearer devices use a clearer member of suitable material which may easily pick off lint and fly carried by the draft rolls, for example, felt, furry cloth, a brush sheet, artificial leather and rubber. There are two types of the clearer devices: the rotary roll type wherein such a clearer member is affixed to a surface of a moving component and kept in contact with the draft rolls and the stationary type wherein the clearer member is secured on a surface of a fixed or stationary component while being in contact with the draft rolls. The former is more useful in long-term, continued operation but less satisfactory as far as clearing performance is concerned. The latter is required to very often remove the fly and failure to do so results in the possibility that the fly accumulated thereon can enter final products. Therefore, a pneumatic clearer has recently been developed and widely used. The mere use of incoming air is however unsatisfactory in removing the accumulated fly and sometimes needs the assistance of brush rolls or the rotary roll type or stationary type clearer. It is general practice to form flutes in the bottom rolls, that is, the draft rolls but the fly or foreign objects enter into the flutes. Accordingly, no complete removal of the fly is assured by only the incoming air.
In order to make use of the advantages of both the rotary type clearer and the stationary type clearer, an apron type of clearer has recently been used which includes the clearer member of an apron shape traveling in contact with the surface of the draft rolls and wiping off the fly at its nonoperative section. The apron type of clearers can be similarly classified into the top apron clearers and the bottom apron clearers. The top and bottom clearers are both installed or one of the both clearers is installed together with the other types of clearers as discussed above.
Of the above clearers, the bottom apron clearer device is needed to be placed below the draft rolls and thus in a limited space so that is should be simple in construction, easy to manipulate and ensure stable and satisfactory clearing performances. Specifically, for the bottom apron clearer it is greatly possible that the fly can enter inside the apron. In particular, within a spinning chamber with an air blower, the fly blown off by air tends to enter inside the bottom and top aprons. It is, therefore, necessary for the apron clearer to remove the fly adhering to not only the outer surface but also the inner surface of the clearer.